<!DOCTYPE html>
<!--JavaScript Object Notation-->
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

</body>
<!--josn的key必须用双引号-->
<script>
    var jsonStr = '{"name":"John","age":16,"addr":["北京","上海","深圳"]}';
    alert(jsonStr.name);
    let obj= JSON.parse(jsonStr);
    alert(obj.name);
    let str=JSON.stringify(obj);
    alert(str);
</script>
</html>